The present invention relates to thin card-like portable radio equipment in which an antenna having a high gain is incorporated.
A predominant type of antenna built in portable radio equipment is a loop antenna which is capable of feeding electromagnetic energy around the equipment efficiently to circuitry. A loop antenna has one or more turns forming loops and transforms magnetic fluxes intersecting the loops into electric energy so as to feed it to the circuitry. Generally, a problem with a loop antenna is that as the aperture of the loop or loops decreases, the number of magnetic fluxes intersecting the aperature and, therefore, the antenna gain decreases. Nevertheless, in parallel with the current trend toward miniature portable radio equipment, there is an increasing demand for a miniature built-in loop antenna. In this situation, the antenna gain attainable with miniature radio equipment and, therefore, the communicatable range is limited.